puppetlabs/puppet-docs — pull request #269 by bartavelle (2014-01-09 08:35:21+00:00)
Title: Parenthesis are mandatory with rvalue-functions

This fixes a problem with the reference documentation where it was not
explained that parenthesis are only optional for statement-level
functions.

Here is an example :

$a = function "argument" $b = literal

With the "old" parser, this will result in a parse error. With the new
parser, it seems that it is interpreted like this :

$a = 'function';
'argument';
$b = 'literal';

Which might cause puzzling bugs.